Diet and Nutrition – Carbohydrates
In this post, Sarkari Exam Bank Team is going to share information regarding Diet and Nutrition – Carbohydrates, this biology topic is important for each and every competitive exam all over India. Sarkariexambank.com updates important blogs daily.
The sum total of all the processes starting from taking the food upto its utilisation called nutrition. Depending upon the mode of nutrition, the organisms can be classified as autotrophs and heterotrophs. Autotrophs manufacture their own organic food from inorganic raw materials.
They are of two types, photoautotrophs and chemoautotrophs. Heterotrophs are unable to manufacture their own food. They obtain organic food from outside. All animals, includ- ing man and non-green plants show hetertrophic mode of nutrition. Heterotrophic organisms or heterotrophs obtain all their energy requirements mainly from organic substances like carbohydrates and fats. They derive their foodstuffs directly or indirectly from the plants.
Hetertrophic nutrition is of two types: (i) Saprozoic or saprophytic, (ii) Holozoic. In saprophytic nutrition, as in non-green plants, the organisms secrete starch digesting en- zymes to digest the food and then absorb the nutrients. In saprozoic organisms like the malarial parasite in man and monocystis in earthworm the already digested food is aobsorbed by the process of diffusion. But nutrition in most of free living animals is holozoic. In this type of nutrition, food may be a small organism, a plant or an animal.
Depending upon food, nutritionally animals are:
(i) Herbivores: Feeding on plant food e.g., Goat, Cow, Rabbit.
(ii) Carnivores: feeding on other animals e.g., Lion, Tiger.
(iii) Omnivores: Feeding on all types of food e.g., humans.
(iv) Detrivores: Feeding on detritus or organic remains e.g., Earthworm.
(v) Scavengers: Feeding on carrions (carrion eaters), e.g., Vulture.
(vi) Frugivorous: Feeding on fruits, e.g., Parrot.
(vii) Sanguivores: Taking meal of blood, e.g., Leech, fe- male Mosquito.
(viii) Insectivores: Eating insects, e.g., common bats.
(ix) Cannibals. Eating other members of own species, e.g., many snakes.
The nutritional requirements of man are more complex than those of the other organisms. Man obtains his energy primarily as a result of the oxidation of nutrients seen as glucose, amino acids, and fatty acids, derived from the break- down of carbohydrates, protein and fats. But these digested food stuffs do not constitute the complete diet of an indi- vidual.
A balanced diet should have a proportionate amount of proteins, fats, carbohydrates, minerals, salts, water vita- min content and non-digestible ‘roughage’ which is com- prised of green vegetables. The cellulose found in the rough- age is not digested in man and other carnivorous animals because enzyme cellulase is missing. The food-stuffs used by mankind includes different nutrients like carbohydrates, fats, proteins, minerals, vitamins and water which can broadly be divided into following groups:
(i) Energy yielding food: Carbohydrate and fats,
(ii) Body building food: Protein and minerals,
(iii) Protective food: Vitamin and minerals.
Balanced Diet is the diet that contains all the compo- nents in optimum proportions and quantity required for maintaining the body in perfect state of health, activity and development. Various components of balanced diet are car- bohydrates (60%), fats (25%), proteins (15%), vitamins (traces), minerals (traces) and roughage.
It is starchy and sugar element of diet, the fuel of hu- man body. One gram of carbohydrate provides 4.1 Cal. en- ergy. Its manufactured by green plants through the pro- cess of photosynthesis. Herbivorous animals take it indi- rectly form plants while the carnivorous animals take it indirectly. Liver convert the excess carbohydrate into glycogen and store in itself and muscles.
Glycogen is known as animal starch because it is not produced in plants. Excess carbohydrate is ultimately converted into fat. There are three forms of carbohydrates:
A. Monosacharides (C6H12O6): It is the simplest form and animals can derive energy only in this form. The examples are glucose (dextrose or grape sugar), galac- tose (soluble milk sugar), fructose (fruit sugar).
B. Disacharides (C12 H22 O11): It is formed by hydroly- sis of two monosacharide molecules e.g. sucrose (cane sugar), lactose (milk sugar), maltose (malt sugar). On an average, we have the equivalent of four teaspoons of
C. Polysacharides [Cn (H2 O)n ]: It is a complex form of chains of monosacharides. However, it is difficult to digest the ploysacharides easily. Human can digest all forms of carbohydrates except cellulose. The major polysacharides are starch, glycogen, cellulose, etc.
More details about CARBOHYDRATES
As you know, Living cells receive carbohydrates from blood mostly as glucose. Glucose is also called blood sugar. Normal content of glucose in blood is 80— 100 mg / 100 ml. Glucose is absorbed from alimentary canal. Excess is stored in liver muscles as glycogen. The process of formation of glycogen from glucose is called glycogenesis. When level of blood glucose falls, glycogen of liver is hydrolysed to produce it.
The phenomenon is called glycogenolysis. Excess carbohy- drate of food is changed to fat through the process of lipo- genesis. Pentose sugars are components of nucleotides, co- enzymes and nucleic acids. Daily requirement of an adult is 500 gm.
Refined carbohydrates refers to foods where machin- ery has been used to remove the high fibre bits (the bran and the germ) from the grain. White rice, white bread, sug- ary cereals, and pasta and noodles made from white flour are all examples of refined carbohydrates.
However, Unrefined car- bohydrates still contain the whole grain, including the bran and the germ, so they’re higher in fibre and will keep you feeling fuller for longer – great if you’re trying to lose weight and hate feeling hungry. Examples include wholegrain rice, wholemeal bread, porridge oats and wholewheat pasta.
SIMPLE & COMPLEX CARBOHYDRATES
These are often confused with refined and unrefined carbohydrates, but the terms simple and complex refer to how complicated the chemical structure of a carbohydrate is rather than to whether it’s wholegrain or not. Complex carbohydrates are the most common and are of three kinds:
Glycogen is our body’s major fuel source and is sometimes referred to as blood sugar. It’s formed from glucose, which is found in almost all foods, and is converted into energy.
Starch is only found in plants and, contrary to popular belief, is not fattening (it is the rich sauces, fats and oils often added to pasta, potatoes, rice, noodles and bread that are the culprits).
Fibre (non-starch polysaccharide) is abundant in unrefined carbohydrates, fruit and vegetables, and is important because it helps your body to process waste efficiently and helps you to feel fuller for longer. If you decide to increase the amount of fibre you eat, try to drink more water too. Your body doesn’t digest fibre, so you need the extra water to help it flow through your digestive system with ease. Nutritionists recommend that your dietary intake must include 18g of fibre every day.
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